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1 – 10 of 31WEAR resistance is never the sole requirement of an engineering material. All engineering components have a function to perform and any particular function will impose a series of…
Abstract
WEAR resistance is never the sole requirement of an engineering material. All engineering components have a function to perform and any particular function will impose a series of requirements on the material of manufacture. In the search for improved wear resistance, these other requirements must never be forgotten: no industrially useful material will survive on wear resistance alone.
Somrerk Chandra-Ambhorn, Sompong Chueaprakha and Thamrongsin Siripongsakul
The dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were investigated on oxidation at 700°C with the effects of dissolved nitrogen in the welds. This paper aims to clarify…
Abstract
Purpose
The dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were investigated on oxidation at 700°C with the effects of dissolved nitrogen in the welds. This paper aims to clarify the oxidation behaviors to expand the range of application for Fe-Cr-Mn stainless steel.
Design/methodology/approach
Dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were fabricated using gas tungsten arc welding to investigate the oxidation behavior of the welds at 700°C. Pure Ar and Ar-4%N2 shielding gases were used to evaluate the effects of nitrogen gas. The welds were introduced to the cyclic oxidation test. In each cycle, the furnace was heated up to 700°C, and the temperature was kept at 700°C for 8 h, then the mass gain because of oxidation was examined. The scales after oxidation test were investigated by using scanning electron microscopy with EDX and X-ray diffraction analysis.
Findings
Addition of 4 per cent nitrogen to Ar shielding gas reduced delta-ferrite content in the weld. Ar-4%N2 shielding gas resulted in dissolved nitrogen which helped increase the diffusivities of chromium or oxygen vacancies in the oxide to facilitate the chromia formation at the inner part near the steel substrate. This protective layer can help reduce the Fe outward diffusion, thus reducing mass gain because of iron oxide formation.
Originality/value
The oxidation behavior of dissimilar welds between AISI 304L and Fe-15.6Cr-8.5Mn were investigated at 700°C. The evaluation is beneficial for expanding the range of application of Fe-Cr-Mn stainless steel at high temperature.
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Sourabh Shukla, Awanikumar P. Patil, Ashlesha Kawale, Anand Babu Kotta and Inayat Ullah
Effect of grain size on degree of sensitization (DOS) was been evaluated in Nickel free steel. Manganese and nitrogen contained alloy is a Ni-free austenitic stainless steels…
Abstract
Purpose
Effect of grain size on degree of sensitization (DOS) was been evaluated in Nickel free steel. Manganese and nitrogen contained alloy is a Ni-free austenitic stainless steels (ASS) having type 202 grade. The main purpose of this investigation is to find the effect of recrystallization on the DOS of stainless steel after the thermo-mechanical processing (cold work and thermal aging).
Design/methodology/approach
In the present investigation, the deformation of 202 grade analyzed using X-ray diffraction (XRD) and microstructural testing. Optical microstructure of Ni-free ASS has been done for cold worked samples with thermally aged at 900°C_6 h. Double loop electrochemical potentiodynamic reactivation test used for findings of degree of sensitization.
Findings
Ni-free ASS appears to be deformed more rapidly due to its higher stacking fault energy which gave results in rapid transformation from strain induced martensite to austenite in form of recrystallized grains, i.e. it concluded that as cold work percentage increases more rapidly recrystallization occurs. XRD results also indicate that more fraction of martensite formed as percentage of CW increases but as thermal aging reverted those all martensite to austenite. So investigation gives the conclusion which suggests that with high deformation at higher temperature and duration gives very less DOS.
Originality/value
Various literatures available for 300 series steel related to the effect of cold work on mechanical properties and sensitization mechanism. However, no one has investigated the effect of recrystallization through thermomechanical processing on the sensitization of nickel-free steel.
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Houria Triki and Abdul-Majid Wazwaz
The purpose of this paper is to present a reliable treatment of the Fokas–Lenells equation, an integrable generalization of the nonlinear Schrödinger equation. The authors use a…
Abstract
Purpose
The purpose of this paper is to present a reliable treatment of the Fokas–Lenells equation, an integrable generalization of the nonlinear Schrödinger equation. The authors use a special complex envelope traveling-wave solution to carry out the analysis. The study confirms the accuracy and efficiency of the used method.
Design/methodology/approach
The proposed technique, namely, the trial equation method, as presented in this work has been shown to be very efficient for solving nonlinear equations with spatio-temporal dispersion.
Findings
A class of chirped soliton-like solutions including bright, dark and kink solitons is derived. The associated chirp, including linear and nonlinear contributions, is also determined for each of these optical pulses. Parametric conditions for the existence of chirped soliton solutions are presented.
Research limitations/implications
The paper presents a new efficient algorithm for handling an integrable generalization of the nonlinear Schrödinger equation.
Practical/implications
The authors present a useful algorithm to handle nonlinear equations with spatial-temporal dispersion. The method is an effective method with promising results.
Social/implications
This is a newly examined model. A useful method is presented to offer a reliable treatment.
Originality/value
The paper presents a new efficient algorithm for handling an integrable generalization of the nonlinear Schrödinger equation.
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Nobody concerned with political economy can neglect the history of economic doctrines. Structural changes in the economy and society influence economic thinking and, conversely…
Abstract
Nobody concerned with political economy can neglect the history of economic doctrines. Structural changes in the economy and society influence economic thinking and, conversely, innovative thought structures and attitudes have almost always forced economic institutions and modes of behaviour to adjust. We learn from the history of economic doctrines how a particular theory emerged and whether, and in which environment, it could take root. We can see how a school evolves out of a common methodological perception and similar techniques of analysis, and how it has to establish itself. The interaction between unresolved problems on the one hand, and the search for better solutions or explanations on the other, leads to a change in paradigma and to the formation of new lines of reasoning. As long as the real world is subject to progress and change scientific search for explanation must out of necessity continue.
Current issues of Publishers' Weekly are reporting serious shortages of paper, binders board, cloth, and other essential book manufacturing materials. Let us assure you these…
Abstract
Current issues of Publishers' Weekly are reporting serious shortages of paper, binders board, cloth, and other essential book manufacturing materials. Let us assure you these shortages are very real and quite severe.
The purpose of this paper is to determine both analytically and numerically the existence of smooth, cusped and sharp shock wave solutions to a one-dimensional model of…
Abstract
Purpose
The purpose of this paper is to determine both analytically and numerically the existence of smooth, cusped and sharp shock wave solutions to a one-dimensional model of microfluidic droplet ensembles, water flow in unsaturated flows, infiltration, etc., as functions of the powers of the convection and diffusion fluxes and upstream boundary condition; to study numerically the evolution of the wave for two different initial conditions; and to assess the accuracy of several finite difference methods for the solution of the degenerate, nonlinear, advection--diffusion equation that governs the model.
Design/methodology/approach
The theory of ordinary differential equations and several explicit, finite difference methods that use first- and second-order, accurate upwind, central and compact discretizations for the convection terms are used to determine the analytical solution for steadily propagating waves and the evolution of the wave fronts from hyperbolic tangent and piecewise linear initial conditions to steadily propagating waves, respectively. The amplitude and phase errors of the semi-discrete schemes are determined analytically and the accuracy of the discrete methods is assessed.
Findings
For non-zero upstream boundary conditions, it has been found both analytically and numerically that the shock wave is smooth and its steepness increases as the power of the diffusion term is increased and as the upstream boundary value is decreased. For zero upstream boundary conditions, smooth, cusped and sharp shock waves may be encountered depending on the powers of the convection and diffusion terms. For a linear diffusion flux, the shock wave is smooth, whereas, for a quadratic diffusion flux, the wave exhibits a cusped front whose left spatial derivative decreases as the power of the convection term is increased. For higher nonlinear diffusion fluxes, a sharp shock wave is observed. The wave speed decreases as the powers of both the convection and the diffusion terms are increased. The evolution of the solution from hyperbolic tangent and piecewise linear initial conditions shows that the wave back adapts rapidly to its final steady value, whereas the wave front takes much longer, especially for piecewise linear initial conditions, but the steady wave profile and speed are independent of the initial conditions. It is also shown that discretization of the nonlinear diffusion flux plays a more important role in the accuracy of first- and second-order upwind discretizations of the convection term than either a conservative or a non-conservative discretization of the latter. Second-order upwind and compact discretizations of the convection terms are shown to exhibit oscillations at the foot of the wave’s front where the solution is nil but its left spatial derivative is largest. The results obtained with a conservative, centered second--order accurate finite difference method are found to be in good agreement with those of the second-order accurate, central-upwind Kurganov--Tadmor method which is a non-oscillatory high-resolution shock-capturing procedure, but differ greatly from those obtained with a non-conservative, centered, second-order accurate scheme, where the gradients are largest.
Originality/value
A new, one-dimensional model for microfluidic droplet transport, water flow in unsaturated flows, infiltration, etc., that includes high-order convection fluxes and degenerate diffusion, is proposed and studied both analytically and numerically. Its smooth, cusped and sharp shock wave solutions have been determined analytically as functions of the powers of the nonlinear convection and diffusion fluxes and the boundary conditions. These solutions are used to assess the accuracy of several finite difference methods that use different orders of accuracy in space, and different discretizations of the convection and diffusion fluxes, and can be used to assess the accuracy of other numerical procedures for one-dimensional, degenerate, convection--diffusion equations.
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The purpose of this paper is threefold. First, to provide an account of economic and commercial intelligence work. Second, to make clear the essential differences between it and…
Abstract
The purpose of this paper is threefold. First, to provide an account of economic and commercial intelligence work. Second, to make clear the essential differences between it and library and technical information work. Third, to discuss the implications of these differences for certain views which seem to be currently held in Aslib.
The subject on which I have been asked to speak is ‘The training of translators”. This is not an easy matter, particularly as there can, in the nature of things, be no golden rule…
Abstract
The subject on which I have been asked to speak is ‘The training of translators”. This is not an easy matter, particularly as there can, in the nature of things, be no golden rule for training for a task so complex and varied as that of the translator, especially in technical or scientific matters. I shall make no apology for approaching this subject from a very practical point of view.
The ultimate estimate of the value of any piece of information is measured by the change it creates. This paper considers the problem of utilizing information under three headings: